Shooting weapons such as guns and crossbows may include telescopic sights (herein referred to as “scopes”) to assist the shooter in properly aligning the shooting weapon with a target before shooting. Such scopes are generally mounted to the top of the shooting weapon vertically over the barrel via mounting hardware such as two split-ring clamps or the like. The hardware may be attached to the weapon via screws, via a mounting rail interface, etc. Once attached to the weapon by the mounting hardware, the scope will be generally aligned with the barrel due to the configuration of the weapon, mounting hardware and scope. However, accurate use of such a scope generally requires a “sighting in” of the scope to align it horizontally and/or vertically with the barrel more precisely. Also, depending on a particular desired target distance and shooting conditions, it is often desirable to further adjust the scope alignment relative to the barrel so that a target centered in the scope is hit.
Most scopes include sighting assisting elements called reticles, which are small markings visible to the shooter when looking through the scope. One common reticle includes two perpendicular “cross-hairs” intended to be oriented with one line being vertical and one line being horizontal. For accurate shooting, it is generally desired to have the target in the scope appear to the user to be the point where the cross-hairs cross before firing. On many scopes, rotatable knobs called turrets are provided to allow the user to adjust the scope central axis either horizontally (i.e., windage adjustment) or vertically (i.e., elevation adjustment) to effectively move the apparent location of the reticle to the user. Therefore, if a shot is taken at a target but the shot falls several inches below the target, the user would turn the elevation turret sufficiently to move the reticle until further shots no longer fall below the target. Such sighting in can be done at one or more target distances (e.g., 100 yards, 200 yards, etc.) until a scope is aligned as desired (sometimes called “zeroed.”)
Some reticles include additional markings such as range indicating circles, cross-hatches, etc., to help further refine targeting during sighting in or later shooting. The reticle additional markings may be arranged in units such as MOA (minute of angle) or mils (milliradians), depending on the scope. If so, the turrets often provide a haptic and audible click when passing certain adjustment units to assist with aligning the scope. For example, rotating an MOA turret might adjust the scope by ¼ MOA per click, which would correspond to ¼ inch movement of the shot relative to the target at 100 yards, or ½ inch at 200 yards. By rotating one of the turrets, the user is moving the aim of the scope via a mechanism arranged between the turret and the scope. After the scope is sighted in to a desired level of accuracy and the user is later firing the gun at different targets, the user can use the reticles with hashmarks, circles, etc., to adjust the aim by moving the perceived location of a desired target away from the center of the cross-hairs or the user can use the turrets to dial in an adjustment that places the desired target at the center of the cross-hairs (both based on information as to distance to target or conditions).
Regardless of the scope attachment hardware, type of reticle, reticle submarkings, etc., it is important to the sighting in and later use of the scope that the scope/reticle itself is aligned. A misaligned reticle (sometimes called “canted” reticle) leads to inaccuracy.
For example, FIG. 1 shows a view s through a conventional cross-hair scope with hashmarked cross-hairs (elevation e and windage w) aligned with respective Cartesian-type directions (vertical v and horizontal h). FIG. 2 shows the same view s, but with cross-hairs canted by angle a indicating that the scope is rotated clockwise from the user's viewpoint around its sighting axis relative to the Cartesian-type directions. If the reticle cross-hairs of a scope are canted in such fashion, the sighting-in adjustments and the in-field targeting adjustments (whether simply visual or via turret adjustment) will be off accordingly. Reticle alignment becomes even more important to accuracy of a shot when its target is further away.
Typically, reticle alignment includes, after attaching the mounting hardware to the gun and placing the scope (loosely) in the mounting hardware, aligning the scope by rotating the scope axially until that the reticle is located in a desired orientation. If the reticle is a cross-hair reticle, the desired orientation has the vertical line oriented vertically. Once aligned the mounting hardware can be tightened around the scope (for example, by fully tightening screws or clamps holding the scope in place in the mounting hardware).
Achieving such reticle alignment has been a multistep process. First, the shooting weapon is loosely placed on a bench rest or in a gun vise. Then, the shooting weapon is oriented so that the barrel is aligned so that a vertical plane through the central axis of the gun barrel is vertical. This alignment is typically done using a bubble level placed on the shooting weapon. Once the shooting weapon is aligned, if the gun vise/bench rest can be tightened, such is done to hold the shooting weapon in place. Next, the scope (loosely aligned to the shooting weapon already in a scope mount) is oriented, typically by placing the bubble level on a flat upper alignment surface of the scope provided for receiving a bubble level or the like. Typically, the flat upper surface is located along the top of the elevation turret. Scope manufacturers generally ensure such flat upper surface is oriented so as to be perpendicular to a vertical reticle line (such as a vertical cross-hair) and parallel to a horizontal reticle line (such as a horizontal cross-hair). Once the upper surface is level (with the vertical reticle portion accordingly being vertical), the scope is considered aligned to the weapon, and the mount can be tightened to hold the scope in place.
Such a method may introduce several possible errors. First, bubble levels are generally not highly accurate, and may introduce errors on the order of one degree or greater. Second, if the shooting weapon itself is not accurately aligned initially, then the step of aligning the scope reticle afterward would be futile by the degree of initial misalignment. Using a bubble level for both alignments compounds the potential for error. Bumping or disturbing the shooting weapon once aligned, if noticed, requires the user to restart the process and, if not noticed, leads to further inaccuracy. Even if a levelling device more accurate than a bubble level were used (such as what is commonly called a “digital protractor”), the above method still introduces potential inaccuracy due to the multi-step alignment process and possibility of disturbing the initial alignment before the reticle alignment is complete.
Thus, while existing scope alignment devices and methods generally work for their intended purposes, improvements to such devices and/or methods that were less cumbersome, less inaccurate, and/or less time consuming, and/or that addressed one of the drawbacks of existing devices, systems, or methods, and/or other issues, would be welcome.